Origin of the name OWAIN.
Etymology of the
name OWAIN.
Meaning of the baby name OWAIN.

OWAIN.Arthurian. The son of Urien. The Welsh form of
Irish Eóghan
(q.v.), meaning "young warrior," from êoghunn
("youth"). It is Anglicized Owen.
Also see Yvaine
and Ywaine.

Owain, in Brittany, continued
popular in Wales, though, perhaps, rather more usual at a late than an
early period. The notable Owen Glendower, as Shakespeare has
taught us to call him, was really Owain ap Gruffydd of Glendfrdwy, his
estate in Merionethshire, where he kept a grand household.
Owain is so like the word oen that in Welsh
stands for a sheep or lamb, that it is generally so translated; but it
is most likely that this is a case of an adaptation of a derivative from
an obsolete word to a familiar one, and that Owen (and Owain) ought to
be carried much further back to the same source as the Erse Eoghan...
(History of Christian Names, Yonge, 1884)